I am using jboss\'s rest-easy multipart provider for importing a file. I read here http://docs.jboss.org/resteasy/docs/1.0.0.GA/userguide/html/Content_Marshalling_Providers.html
It seems that Isim is right, but there is a workaround.
Create a hidden field in your form and update its value with the selected file's name. When the form is submitted, the filename will be submitted as a @FormParam.
Here is some code you could need (jquery required).